Lamination of electrochromic device to glass substrates

ABSTRACT

Electrochromic device laminates and their method of manufacture are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/178,065, filed Jul. 7, 2011, which is a continuation of U.S.application Ser. No. 13/040,787, filed Mar. 4, 2011, and which claimsthe benefit of the filing dates of U.S. Provisional Patent ApplicationNos. 61/311,001, filed Mar. 5, 2010, and 61/412,153, filed Nov. 10,2010, the disclosures of which are hereby incorporated herein byreference.

BACKGROUND OF THE INVENTION

Glass, especially glass that is tinted, is subjected to large stressesdue to non-uniform heating caused by the absorption of solar radiation.These stresses can be so great as to cause fractures or cracks todevelop in the glass, which could ultimately lead to failure.

The center of the glass (COG) may have a considerably higher temperaturethan, for example, the edges of the glass, which are typically coveredor shadowed by a frame or other architectural structure. Of course, themore tinted the glass, the greater the solar absorption, and the largerthe potential temperature differential between the COG and the glassedges or other shaded areas. This results in stress, typically along theglass edges, which if greater than about 14 to about 28 MPa, couldresult in cracking. As such, normal practice dictates that glass beheat-strengthened or tempered to reduce the incidence of fracture.Typically, the absorbing glass pane is heat-treated or tempered so as towithstand at least about 35 MPa, or to conform with industry standards,such as ASTM E2431 (Practice for Determining the Resistance of SingleGlazed Annealed Architectural Flat Glass to Thermal Loadings). Ofcourse, this adds to the cost of manufacturing.

Like tinted glasses, electrochromic devices (hereinafter “EC devices”)absorb significant amounts of solar radiation, especially when in afully darkened state. To withstand the stresses or service loadsassociated with these temperature differentials, it is common practiceto use heat-strengthened or tempered glass as the substrate for thesedevices. While this is a practical solution, the cost of manufacturingdevices based on these substrates is expensive. It is desirable toreduce costs and increase efficiency in the manufacture of EC devices,while maintaining their structural stability (i.e. their ability towithstand cracking and failure both during the manufacturing process andwhen installed in the field).

Traditional EC devices and the insulated glass units (IGUs) comprisingthem have the structure shown in FIG. 1A. As used herein, the term“insulated glass unit” means two or more layers of glass separated by aspacer along the edge and sealed to create a dead air space (or othergas, e.g. argon, nitrogen, krypton) between the layers. The IGU 18comprises an interior glass panel 10 and an EC device 19. The EC device19 is comprised of an EC stack 11 comprising a series of applied ordeposited films on the EC substrate 12. The EC substrate 12 istraditionally comprised of glass which has been heat-strengthened ortempered.

To form the IGU 18, a glass panel, which will become the EC substrate12, is first cut to a custom size according to the dimensions needed.The cut glass panel 12 is then tempered or heat-strengthened to providesufficient strength to endure fabrication stresses and stressesencountered during its service life (“service loads”). The EC devicestack 11, comprising, for example, a series of thin films, is thenapplied or deposited to the glass panel 12 by methods known in the art(see, for example, U.S. Pat. Nos. 7,372,610 and 7,593,154, thedisclosures of which are incorporated by reference herein). Cutting ofthe glass panel 12 is not performed after tempering or heatstrengthening. Likewise, the substrate of an EC device 19 is generallynot tempered or heat-strengthened after the films forming the EC stack11 are deposited (unless using a suitably post-temperable EC films stackand process). The IGU 18 is then assembled by combining the EC device 19with another glass panel 10. The two panels are separated by spacers 17.Panel 10 may contain thin film coatings on either side (e.g. for solarcontrol).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a is a cut-away view of a traditional IGU comprising an EC device.

FIG. 1b is a cut-away view of an IGU comprising an EC device, where theEC device is itself a laminate of two materials.

FIG. 2 is a plot of stress distribution of an EC laminate comprising alow coefficient of thermal expansion glass laminated to a soda-limeglass.

FIG. 3a is a plot of EC laminates comparing peak edge tensile stressesfor several laminates exposed to solar irradiation.

FIG. 3b is a plot of an EC laminate comparing peak edge tensile stressesfor several laminates exposed to solar irradiation.

FIG. 4 provides a summary of impact testing as a function of ECsubstrate, EC outer laminate glass pane, and interlayer thicknesses.

FIG. 5 provides an example of a four-point bend test showing a laser-cutglass sample under testing conditions.

FIG. 6. provides a probability plot of strength for glass samplescomparing mechanical cut and laser cut panels.

SUMMARY OF THE INVENTION

Applicants have developed an improved IGU comprising an EC devicelaminate. Applicants have also developed a method of manufacturing theimproved EC device laminate and IGU.

In one aspect of the present invention, Applicants have discovered aprocess of manufacturing an electrochromic device laminate comprising:(a) providing an electrochromic substrate; (b) cutting theelectrochromic substrate into one or more substrate daughter panes; (c)fabricating a plurality of electrochromic device precursors on each ofthe one or more substrate daughter panes; (d) cutting each of theelectrochromic device precursors into individual electrochromic devices;and (e) laminating each of the individual electrochromic devices to aseparate outer laminate glass pane (an example of the“cut-then-coat-then-cut” process described further herein). In oneembodiment, the electrochromic device precursors are mechanically cut.In another embodiment, the electrochromic device precursors are lasercut. In another embodiment the EC device is cut by electrothermalcutting.

In another embodiment, the individual electrochromic devices have anedge strength of at least about 60 MPa. In another embodiment, theindividual electrochromic devices have an edge strength of at leastabout 69 MPa. In another embodiment, the individual electrochromicdevices have an edge strength of at least about 75 MPa. In anotherembodiment, the individual EC devices have an edge strength of at leastabout 100 MPa.

In another embodiment, the individual electrochromic devices are aboutthe same size as the outer laminate glass pane. In another embodiment,the individual electrochromic devices are smaller than the outerlaminate glass pane in at least one dimension. In another embodiment,the individual electrochromic devices are indented about 0.5 mm to about3 mm relative to the outer laminate glass pane in at least onedimension. In another embodiment, the individual electrochromic devicesare indented about 1 mm to about 2.0 mm relative to the outer laminateglass pane in at least one dimension, preferably in all dimensions.

In another embodiment, the electrochromic substrate and the outerlaminate glass pane comprise the same material. In another embodiment,the electrochromic substrate is a different material than the outerlaminate glass pane. In another embodiment, a material for theelectrochromic substrate is selected from the group consisting of lowcoefficient of thermal expansion glass, soda-lime float glass,aluminosilicate glass, borofloat glass, boroaluminosilicate glass, otherlow-sodium composition glasses or a polymer. In another embodiment, theelectrochromic substrate has a coefficient of thermal expansion rangingfrom about 2 ppm/K to about 10 ppm/K for glass substrates and up toabout 80 ppm/K for polymer substrate materials. In another embodiment,the electrochromic substrate has a coefficient of thermal expansionranging from about 4 ppm/K to about 8 ppm/K. In another embodiment, theelectrochromic substrate has a thickness ranging from about 0.7 mm toabout 6 mm.

In another embodiment, a material for the outer laminate glass pane isselected from the group consisting of low coefficient of thermalexpansion glass, soda-lime float glass, aluminosilicate glass, borofloatglass, boroaluminosilicate glass, heat-strengthened glass, temperedglass, or a polymer. In another embodiment, the outer laminate glasspane has a coefficient of thermal expansion ranging from about 2 ppm/Kto about 10 ppm/K. For polymer-based substrates, the coefficient ofthermal expansion can be up to about 80 ppm/K. In another embodiment,the outer laminate glass pane has a thickness ranging from about 2.3 mmto about 12 mm. In another embodiment, the interlayer material isselected from the group consisting of polyvinylbutyral, ionomericpolymers, ethylenevinyl acetate, polyurethanes, or mixtures thereof.

Another aspect of the present invention is a laminate prepared accordingto the “cut-then-coat-then-cut” process. In another embodiment, thelaminate prepared according to the “cut-then-coat-then-cut” processcomprises a substrate having an edge strength of at least about 60 MPa.

In another aspect of the present invention, Applicants have discovered aprocess of manufacturing an electrochromic device laminate comprising:(a) providing an electrochromic substrate; (b) fabricating a pluralityof electrochromic device precursors on the electrochromic substrate; (c)cutting each of the electrochromic device precursors into individualelectrochromic devices; and (d) laminating each of the individualelectrochromic devices to a separate outer laminate glass pane (anexample of the “coat-then-cut” process described further herein). The ECdevice precursors may be cut mechanically by laser, or by electrothermalcutting.

In another embodiment, the individual electrochromic devices have anedge strength of at least about 60 MPa. In another embodiment, the edgestrength is at least about 69 MPa. In another embodiment, the edgestrength is at least about 75 MPa. In another embodiment, the edgestrength is at least about 100 MPa.

In another embodiment, the individual electrochromic device is about thesame size as the outer laminate glass pane. In another embodiment, theindividual electrochromic device is smaller than the outer laminateglass pane in at least one dimension. In another embodiment, theindividual electrochromic device is indented about 0.5 mm to about 3 mmrelative to the outer laminate glass pane in at least one dimension. Inanother embodiment, the individual electrochromic device is indentedabout 1 mm to about 2.0 mm relative to the outer laminate glass pane inat least one dimension.

In another embodiment, the annealed glass substrate and the outerlaminate glass pane comprise the same material. In another embodiment,the electrochromic substrate is a different material than the outerlaminate glass pane. In another embodiment, a material for theelectrochromic substrate is selected from the group consisting of lowcoefficient of thermal expansion glass, soda-lime float glass,aluminosilicate glass, borofloat glass, boroaluminosilicate glass,low-sodium composition glasses, or a polymer. In another embodiment, theelectrochromic substrate has a coefficient of thermal expansion rangingfrom about 2 ppm/K to about 10 ppm/K. For polymer-based substrates, thecoefficient of thermal expansion can be up to about 80 ppm/K. In anotherembodiment, the electrochromic substrate has a coefficient of thermalexpansion ranging from about 4 ppm/K to about 8 ppm/K. In anotherembodiment, the electrochromic glass substrate has a thickness rangingfrom about 0.7 mm to about 6 mm.

In another embodiment, a material for the outer laminate glass pane isselected from the group consisting of low coefficient of thermalexpansion glass, soda-lime float glass, aluminosilicate glass, borofloatglass, boroaluminosilicate glass, heat-strengthened glass, temperedglass, or a polymer. In another embodiment, the outer laminate glasspane has a coefficient of thermal expansion ranging from about 2 ppm/Kto about 10 ppm/K. In another embodiment, the out laminate glass panehas a thickness ranging from about 2.3 mm to about 12 mm. In anotherembodiment, the interlayer material is selected from the groupconsisting of polyvinylbutyral, ionomeric materials, ethylenevinylacetate, polyurethanes, or mixtures thereof.

Another aspect of the invention is a laminate prepared according to the“coat-then-cut” process. In another embodiment, the laminate preparedaccording to the coat-then-cut process comprises a substrate having anedge strength of at least about 60 MPa.

In another aspect of the present invention, Applicants have discovered alaminate comprising: (a) an electrochromic device, said electrochromicdevice comprising an electrochromic stack on an annealed glasssubstrate; (b) an outer laminate glass pane; and (c) an interlayermaterial sandwiched between the electrochromic device and the outerlaminate glass pane. In some embodiments, the electrochromic device hasan edge strength of at least about 60 MPa. In another embodiment, theedge strength is at least about 69 MPa. In another embodiment, the edgestrength is at least about 75 MPa, and in other embodiments at leastabout 100 MPa. In another embodiment, the electrochromic device isprepared by mechanical cutting. In another embodiment, theelectrochromic device is prepared by laser cutting. In anotherembodiment, the electrochromic device is prepared by electrothermalcutting. In another embodiment, the laminate is part of an integratedglass unit.

In another embodiment, the annealed glass substrate and the outerlaminate glass pane comprise the same material. In another embodiment,the annealed glass substrate is a different material than the outerlaminate glass pane. In another embodiment, a material for the annealedglass substrate is selected from the group consisting of low coefficientof thermal expansion glass, soda-lime float glass, aluminosilicateglass, borofloat glass, boroaluminosilicate glass, low-sodiumcomposition glass, or a polymer. In another embodiment, the annealedglass substrate has a coefficient of thermal expansion ranging fromabout 2 ppm/K to about 10 ppm/K. In another embodiment, the annealedglass substrate has a coefficient of thermal expansion ranging fromabout 4 ppm/K to about 8 ppm/K. In another embodiment, the annealedglass pane has a thickness ranging from about 0.7 mm to about 6 mm. Inanother embodiment, the annealed glass pane has the same thickness asthe outer laminate. In another embodiment, the annealed glass pane has adifferent thickness than the outer laminate.

In another embodiment, a material for the outer laminate glass pane isselected from the group consisting of low coefficient of thermalexpansion glass, soda-lime float glass, aluminosilicate glass, borofloatglass, boroaluminosilicate glass, heat-strengthened glass, temperedglass, or a polymer. In another embodiment, the outer laminate glasspane has a coefficient of thermal expansion ranging from about 2 ppm/Kto about 10 ppm/K. In another embodiment, for polymer-based substrates,the coefficient of thermal expansion can be up to about 80 ppm/K. Inanother embodiment, the outer laminate glass pane has a thicknessranging from about 2.3 mm to about 12 mm.

In another embodiment, the annealed glass substrate is about the samesize as the outer laminate glass pane. In another embodiment, theannealed glass substrate is smaller than the outer laminate glass panein at least one dimension. In another embodiment, the annealed glasssubstrate is indented about 0.5 mm to about 3 mm relative to the outerlaminate glass pane in at least one dimension. In another embodiment,the annealed glass substrate is indented about 1 mm to about 2.0 mmrelative to the outer laminate glass pane in at least one dimension. Inanother embodiment, a perimeter of the smaller annealed glass substrateis surrounded on at least one side by interlayer material or anothermaterial, such as a polymer including silicones, urethanes, epoxies, andacrylates.

In another embodiment, the interlayer material is selected from thegroup consisting of polyvinylbutyral, ionomeric materials, ethylenevinylacetate, polyurethanes, or mixtures thereof.

In another embodiment, the annealed glass substrate is soda-lime floatglass having a coefficient of thermal expansion of about 8.5 ppm/K, saidouter laminate glass pane is tempered soda-line float glass having acoefficient of thermal expansion of about 8.5 ppm/K, and the interlayermaterial is polyvinylbutyral. In another embodiment, the interlayermaterial is SentryGlas® Plus (SGP). In another embodiment, the annealedglass substrate is prepared by laser cutting and has an edge strength ofat least 69 MPa. In another embodiment, the electrochromic stack isbetween the annealed glass substrate and the interlayer material. Inanother embodiment, the electrochromic stack is on a surface of theannealed glass substrate opposite of the interlayer material.

In another aspect of the present invention, Applicants have discovered alaminate comprising: (a) an electrochromic device, said electrochromicdevice comprising an electrochromic stack on a substrate; (b) an outerlaminate glass pane; and (c) an interlayer material sandwiched betweenthe electrochromic device and the outer laminate glass pane. In anotherembodiment, the electrochromic device is prepared by laser cutting orelectrothermal cutting.

Applicants have unexpectedly found that the electrochromic devicelaminates (or IGUs comprising these laminates) of the present inventioncan withstand stresses similar to those encountered by traditionalelectrochromic devices manufactured on tempered or heat-treated glasssubstrates (or IGUs comprising such traditional electrochromic devices).As such, the EC device laminate of the present invention can withstandsimilar center of glass and edge stresses, and can withstand stresses ofat least about 17 MPa.

In some embodiments, by withstanding similar stresses it is meant thatthat the electrochromic device laminates or IGUs of the presentinvention pass about the same industry standard tests as traditionalelectrochromic devices or IGUs. In other embodiments, by withstandingsimilar stresses it is meant that that the electrochromic devicelaminates or IGUs of the present invention can withstand (i) stressessafely in excess of maximum in-service thermomechanical stressesencountered in traditional EC applications, and/or (ii) at least about50% of the same service loads or stresses as traditional EC devices orIGUs. Applicants have also surprisingly found that that these objectivescan be achieved using annealed glass substrates upon which theelectrochromic stack is applied or deposited.

Applicants have unexpectedly found that the improved methods ofmanufacturing provide for electrochromic device laminates or IGUs thatcan withstand service loads or stresses similar to those encountered byIGUs produced by traditional means, while providing enhancedmanufacturing efficiency and meeting industry standards.

Moreover, Applicants have surprisingly discovered that annealed glasssubstrates can be laser cut to produce a sufficiently defect free edgethat will, it is believed, endure the full range of thermal and loadstresses that the EC device laminate will be subjected to during itsservice life. Applicants have tested the laser cut glass and the ECdevice laminates of FIG. 1B at the high end of the thermal andmechanical stress parameter space and have determined that laser cut, ECdevice laminates or substrates are highly durable and suitable for usein residential and commercial architectural applications and otherapplications.

Moreover, Applicants have found that the “coat-then-cut” and“cut-then-coat-then-cut” processes, both described further herein, allowfor coating of large substrate panels and custom sizing after coating.Applicants have also found that this process provides improved processcontrol and better overall uniformity of the film coatings of the ECdevice. Indeed, it is believed that when glass panels all having aboutthe same dimensions are used, subsequent processing temperatures andsputtering plasma conditions for each and every panel will be about thesame. This leads, it is believed, to more efficient, continuous coateror sputter operation without the need to slow or stop production or tomake process adjustments for the many glass thicknesses, tints, andsizes desired. Thus, throughput rate and uptime are maximized, resultingin lower, more competitive product costs when manufacturingelectrochromic devices or IGUs.

DETAILED DESCRIPTION

EC Device Laminate

One aspect of the present invention is an EC device laminate comprisingan electrochromic device, the electrochromic device comprising anelectrochromic stack on an EC substrate; an EC outer laminate glasspane; and an interlayer material sandwiched between the electrochromicdevice and the outer laminate glass pane.

The EC device laminate 29 and IGU 30 containing it are shown in FIG. 1B.EC device laminate 29 is comprised of an EC device 32 laminated to an ECouter laminate glass pane 22. Between the EC device 32 and the EC outerlaminate glass pane 22 is an interlayer material 28 which bonds the ECdevice 32 and the outer laminate pane 22. The EC device 32 is itselfcomprised of an EC stack 21 which is applied or deposited on an ECsubstrate 31. The completed IGU 30 comprises the EC device laminate 29together with another glass panel 20, separated by spacers 27. FIG. 1Brepresents a two pane IGU, however, the invention also contemplates IGUscontaining three or more panes (the additional panes may be any shape orsize and comprise any coating, tinted or otherwise, known in the art).

Any EC stack 21 may be used as known to those of skill in the art.Exemplary EC stacks are described, for example, in U.S. Pat. Nos.5,321,544; 5,404,244; 7,372,610; and 7,593,154, the disclosures of whichare incorporated by reference in their entirety herein.

In one embodiment, at least the EC substrate 31 of the EC devicelaminate 29 is comprised of annealed glass. As used herein, the term“annealed glass” means glass produced without internal stresses impartedby heat treatment and subsequent rapid cooling. This includes glasstypically classified as annealed glass or float glass and only excludesheat-strengthened glass or tempered glass.

In other embodiments, both the EC substrate 31 and the EC outer laminateglass pane 22 are comprised of annealed glass. In embodiments where ECsubstrate 31 and EC outer laminate glass pane 22 are both comprised ofannealed glass, the annealed glass utilized may be the same (“matched”)or different (“mismatched”). The annealed glass substrates used may alsohave the same or different coefficients of thermal expansion ordifferent types and/or amounts of dopants.

For example, in a “mismatched” embodiment, substrate 31 may be comprisedof soda-lime float glass while EC outer laminate glass pane 22 iscomprised of low coefficient of thermal expansion glass (low CTE glass),or vice versa. In a “matched” embodiment, by way of example, substrate31 and EC outer laminate glass pane 22 may both be comprised ofsoda-lime float glass or, alternatively, both may be comprised of lowCTE glass.

In addition to as defined above, the term “mismatched” also means theuse of glass having different thicknesses, regardless of whether thetype of glass is the same or different. For example, substrate 31 andouter laminate glass pane 22 could be of the same material, but havedifferent thicknesses. Or, by way of example only, substrate 31 can beof a material that is different than outer laminate glass pane 22 andhave different thicknesses. Further, by way of example only, substrate31 can be of a material that is the same type as outer laminate glasspane 22 but have a different coefficient of thermal expansion and/ordifferent thickness.

The EC substrate 31 of the present invention may be selected fromtraditional glass materials including soda-lime annealed glass, such asfrom Guardian Industries (Guardian Global Headquarters, Auburn Hills,Mich.), Pilkington, North America (Toledo, Ohio), Cardinal GlassIndustries (Eden Prairie, Minn.), and AGC (AGC Flat Glass, Alpharetta,GI), who produce large area thin glass.

The EC substrate 31 may also be selected from materials including lowCTE borofloat glass, such as that available from Schott (Schott NorthAmerica Elmsford, N.Y.), or boroaluminosilicate glasses such as Corning1737™, and Corning Eagle XG™ (each of which are available from CorningIncorporated, Corning, N.Y.). Moreover, the EC substrate 31 may beselected from materials including aluminosilicate glass. Those skilledin the art will be able to select other glass substrates suitable forthis purpose and meeting the limitations of the claimed invention.

The EC substrate 31 may also be comprised of a polymer, copolymer, ormixtures of one or more polymers or copolymers. Nonlimiting examples ofpolymers include polyimide, polyethylene, napthalate (PEM), polyethyleneteraphthallate (PET), aramid or other similar polymer materials. Thoseskilled in the art will be able to select other polymeric substratessuitable for this purpose and meeting the limitations of the claimedinvention.

In general, the EC substrate 31 may have any thickness depending on thedesired application (e.g. residential architectural window, commercialarchitectural window, or even an automotive window) and desiredthermal/structural properties. Typically, substrate 31 has a thicknessranging between about 0.7 mm and about 6 mm. In some embodiments, ECsubstrate 31 has a thickness ranging from between about 1.5 mm and about2.3 mm.

In some embodiments, the annealed glass or soda-lime float glassutilized has a coefficient of thermal expansion (CTE) of between about7.0 ppm/K and about 10.0 ppm/K. In other embodiments, the soda-limefloat utilized glass has a CTE of between about 8.2 ppm/K and about 9.0ppm/K. In some embodiments utilizing low-CTE glasses, the coefficient ofthermal expansion ranges from about 2.0 ppm/K to about 6.4 ppm/K. Insome specific embodiments utilizing low-CTE glasses, the coefficient ofthermal expansions are as follows: Corning 1737 (about 3.76 ppm/K),Corning EagleXG™ (about 3.2 ppm/K) and Schott Borofloat 33™ (about 3.3ppm/K).

The EC outer laminate glass pane 22 of the present invention may beselected from materials including heat-strengthened glass, temperedglass, partially heat-strengthened or tempered glass, or annealed glass.“Heat-strengthened glass” and “tempered glass”, as those terms are knownin the art, are both types of glass that have been heat treated toinduce surface compression and to otherwise strengthen the glass.Heat-treated glasses are classified as either fully tempered orheat-strengthened. According to Federal Specification DD-G-1403B, fullytempered glass must have a surface compression of about 69 MPa or morefor an edge compression of about 67 MPa or more. It is believed thatheat-strengthened glass must have a surface compression between about 24and about 69 MPa, or an edge compression between about 38 and about 67MPa. The fracture characteristics of heat-strengthened glass, it isbelieved, vary widely and fracture can occur at stresses from about 41to above 69 MPa.

In general, the EC outer laminate glass pane 22 may have any thicknessdepending on the desired application (e.g. residential architecturalwindow or commercial architectural window) and desiredthermal/structural properties. In some embodiments, the EC outerlaminate pane 22 may be comprised of plastics, including polycarbonates.Typically, the EC outer laminate glass pane 22 has a thickness rangingbetween about 2.3 mm and about 12 mm. In some embodiments, EC outerlaminate glass pane 22 has a thickness ranging from between about 2.3 mmand about 6 mm. Of course, thicker glass may be utilized should theapplication require it, e.g. when used in architectural applicationsexperiencing high wind loads or for ballistic- or blast-resistantapplications.

In some embodiments, the annealed glass or soda-lime float glassutilized has a coefficient of thermal expansion (CTE) of between about7.0 ppm/K and about 10.0 ppm/K. In other embodiments, the soda-limefloat glass has a CTE of between about 8.2 ppm/K and about 9.0 ppm/K. Insome embodiments utilizing low-CTE glasses, the coefficient of thermalexpansion ranges from about 2.0 ppm/K to about 6.4 ppm/K. In somespecific embodiments utilizing low-CTE glasses, the coefficient ofthermal expansions are as follows: Corning 1737™, about 3.76 ppm/K;Corning EagleXG™, about 3.2 ppm/K; and Schott Borofloat 33™, about 3.3ppm/K.

In some embodiments, the EC substrate 31 and EC outer laminate glasspane 22 have about the same coefficient of thermal expansion (CTE). Inother embodiments, the EC substrate 31 and EC outer laminate glass pane22 have different CTEs. In other embodiments, the EC substrate 31 and ECouter laminate glass pane 22 have a coefficient of thermal expansionthat differs by less than about 50%. In yet other embodiments, the ECsubstrate 31 and EC outer laminate glass pane 22 have a coefficient ofthermal expansion that differs by less than about 30%. In furtherembodiments, the EC substrate 31 and EC outer laminate glass pane 22have a coefficient of thermal expansion that differs by less than about20%. In yet further embodiments, the EC substrate 31 and EC outerlaminate glass pane 22 have a coefficient of thermal expansion thatdiffers by less than about 10%. As discussed herein, the selection of anappropriate interlayer material 28 may assist in mitigating any stressescaused by a CTE mismatch.

For example, FIG. 2 shows the stress distribution of a laminate when lowCTE glass is used as the EC substrate 31, soda-lime glass is used as theEC outer laminate pane 22, and polyvinylbutyral is used as theinterlayer material 28. The simulation shows the shadowing effect of a25 mm frame around the edge of the panel. It is believed that the framecauses a temperature gradient between the edge and center of thelaminate, thereby, it is believed, causing formation of edge stresses.In the case of a laminate structure, a mismatch in CTE causes additionalstresses as solar absorption causes the device to heat up. The effect ofthis CTE mismatch is shown in FIG. 3a , in which a solar absorbing lowCTE/soda-lime glass laminate subject to 1000 W/m² incident radiation hasa higher peak stress level compared to a soda-lime/soda-lime laminatestructure under the same solar absorption conditions, also shown in FIG.3a . As shown in these examples, maximum edge stress changes over timeas the EC laminate absorbs more solar radiation, up to a maximum stressof about 20.5 MPa after approximately 40 minutes. At longer times, heatconduction through the glass from the exposed region to the shadowededge region will cause the temperature to equilibrate and correspondingthermal stresses to decrease from their peak level. It is believed thatthese stresses may be reduced when two low CTE panels are laminatedtogether, such as shown in FIG. 3b , under the same edge frame shadowand solar absorption conditions as shown in FIG. 3 a.

In preferred embodiments, the edge of EC substrate 31 is protected fromhandling and mechanical damage. Without wishing to be bound by anyparticular theory, it is believed that if the edges of EC substrate 31are significantly nicked or chipped, the overall strength of the ECdevice could be compromised. In some embodiments of the presentinvention, the EC substrate 31 is indented relative to EC outer laminateglass pane 22. In other embodiments, the size of the EC substrate 31 isslightly smaller than the size of the EC outer laminate glass pane 22,in at least one dimension, preferably in at least two dimensions, andmore preferably in all dimensions. In some embodiments, EC substrate 31is indented about 0.5 mm to about 3 mm in at least one dimension, andpreferably about 0.5 mm to about 3 mm around the perimeter, with respectto glass pane 22. In other embodiments, EC substrate 31 is indentedabout 1 mm to about 2.0 mm, in at least one dimension, and preferablyabout 1 mm to about 2.0 mm around the perimeter with respect to glasspane 22.

In some embodiments, the depth of the indentation is determined by theautomated placement tolerances of the two pieces of glass during thelamination layup/manufacturing process as well as any slight movementsincurred during the thermal lamination process. In some embodiments,during thermal processing the interlayer material is allowed to flowaround the edge of EC substrate 31 providing an element of protectionwhich, it is believed, further protects the EC device laminate 29 fromdamage during shipment and installation. In some embodiments, excessinterlayer material is added to achieve this. In other embodiments,additional protective materials can be deposited around the perimeter ofthe EC device such as polymers (including but not limited to epoxies,urethanes, silicones, and acrylates). These materials can be applied invarying amounts to achieve the desired outcome.

The interlayer material may be selected from any material which allowsfor the EC device 32 to be laminated, by those methods known in the art,to the EC outer laminate glass pane 22. In general, the interlayermaterial 28 should possess a combination of characteristics including:(a) high optical clarity; (b) low haze; (c) high impact resistance; (d)high penetration resistance; (e) ultraviolet light resistance; (f) goodlong term thermal stability; (g) sufficient adhesion to glass and/orother polymeric materials/sheets; (h) low moisture absorption; (i) highmoisture resistance; (j) excellent weatherability; and (k) high stressload resistance (e.g. impact loading or windloading). In someembodiments, the interlayer material 28 at least provides sufficientadhesion to both the EC device 32 and EC outer laminate glass pane 22 inorder to prevent delamination during in-service stress loads and also beselected such that it does not negatively affect the visualcharacteristics of the EC device laminate 29. In other embodiments, theinterlayer material should be selected such that industry standardperformance criteria is satisfied for both loading modes (see, forexample, ANSI Z97.1 for impact testing and ASTM E1300 for windloadcriteria).

In one embodiment, a suitable interlayer material 28 is polyvinylbutyral(PVB), available from Solutia Inc. (St. Louis, Mo.) under the trade nameSaflex™. PVB is also available from DuPont (Wilmington, Del.) under thetrade name Butacite™. Other suitable materials for interlayer material28 include ionomeric materials such as SentryGlas Plus™ (SGP) fromDuPont, ethylenevinyl acetate (EVA) and cross-linking polyurethanes(e.g. cast-in-place resins) or thermoplastic polyurethanes. Of course,mixtures of any of the above identified materials may be used. Inaddition, other polymer materials can be used as an interlayer material28 provided that they satisfy at least some of the thermomechanical,adhesion, and optical transparency functional requirements recitedabove. This also includes interlayer materials composed of compositepolymer layers designed for improved sound attenuation,ballistic-resistant and blast-resistant applications. These materialsare readily available to those of skill in the art.

In other embodiments, the interlayer material 28 may include siliconesand epoxies.

If, for example, the EC substrate 31 and EC outer laminate glass pane 22are comprised of the same material, it is believed that both glasspanels would have about the same coefficient of thermal expansion. Wherethe materials differ, i.e. a mismatch situation such as in FIG. 2,without wishing to be bound by any particular theory, it is believedthat the selection of an appropriate interlayer material 28 could affectthe transfer or distribution of stress between the mismatched glasspanels and therefore, it is believed, relieve at least some of thestresses present at various points in the laminate.

For lamination structures that involve a coefficient of thermalexpansion (CTE) mismatch between the panes of glass, it is believed thatthe interlayer should be selected such that it either be (1) compliantenough not to transmit tensile stresses from the higher CTE glass panelto the lower CTE glass panel; or (2) stiff enough from the laminationtemperature such that compressive stresses would be transmitted from thehigh CTE glass panel to the low CTE glass panel during cooling withnegligible polymer mechanical relaxation at low temperatures.

FIGS. 3a and 3b provide a comparison of peak edge tensile strength for alaminate (where the component panels in this case have thicknesses of0.7 mm and 6 mm, respectively) exposed to solar irradiation, with theedges shadowed by a 1″ window/architectural frame. Matched (low CTE/lowCTE; soda-lime/soda-lime) and mismatched (low CTE/soda-lime) examplesare shown as a function of time. For a stiff interlayer material(stress-transmitting), the effective stress for the low CTE/soda-limecombination may be larger than for the soda-lime/soda-lime combination.As such, it is believed that the resulting edge stress may depend on thethermo-mechanical properties of the interlayer material.

The EC device laminates 29 (or IGUs 30 comprising these laminates) arebelieved to withstand stresses similar to those encountered bytraditional electrochromic devices manufactured on tempered orheat-treated glass substrates (or IGUs comprising such traditionalelectrochromic devices).

In some embodiments, by withstanding similar stresses it is meant thatthat the EC device laminates 29 or IGUs 30 of the present invention passabout the same industry standard tests as traditional electrochromicdevices or IGUs. In other embodiments, by withstanding similar stressesit is meant that that the EC device laminates 29 or IGUs 30 of thepresent invention can withstand (i) stresses safely in excess of maximumin-service thermomechanical stresses encountered in traditional ECapplications, and/or (ii) at least about 50% of the same service loadsor stresses as traditional electrochromic devices or IGUs. In someembodiments, the EC device laminate 29 is able to withstand a thermaledge stress (or service load) of at least about 17 MPa. In otherembodiments, the EC device laminate is able to withstand a thermal edgestress of at least about 21 MPa. In some embodiments, the EC device 29has an edge strength of at least about 60 MPa. In other embodiments, theEC device or EC substrate has an edge strength of at least about 69 MPa.In yet other embodiments, the EC device or EC substrate has an edgestrength of at least about 75 MPa. In even further embodiments, the ECdevice or EC substrate has an edge strength of at least about 100 MPa.

In some embodiments, the EC laminate 29 or EC substrate 31 is part of anIGU. The glass panel 20, which is used to form the IGU, may be selectedfrom any material, including glasses or plastics, traditionally used inIGU structures. For example, any kind of glass (soda-lime glass, low CTEglass, tempered glass, and/or annealed glass) or plastic may be used.Moreover, the glass panel 20 may itself be a multipane laminate of oneor more materials (multiple panes of glass, multiple panes of plastic,alternating glass, plastic panes in any order). The glass panel 20 mayalso be tinted with any color or coated on one or both sides in anytraditional manner, such as chemical or physical vapor depositioncoating. The glass panel 20 may be an electrochromic or thermochromicdevice. The glass panel 20 may be laser cut or be mechanically scribed.Moreover, IGU 30 of FIG. 1B may be a triple pane IGU, i.e. an IGUcontaining an additional glass (or polymer, e.g. acrylic) panel 20adjacent to one of glass panel 20 or EC device laminate 29, butseparated by spacers. Glass panel 20 may have any thickness or have anyproperties, provided it meets minimum commercial or residential buildingcodes and/or window standards.

Methods of Manufacturing

“Coat-then-Cut”

In one embodiment of the proposed invention, Applicants have discovereda manufacturing approach which involves the concept of ‘coat-then-cut’.In one aspect is a process of manufacturing an electrochromic devicelaminate comprising providing an electrochromic substrate; fabricating aplurality of electrochromic device precursors on the substrate; cuttingeach of the electrochromic device precursors into individualelectrochromic devices, and laminating each of the individualelectrochromic devices to a separate outer laminate glass pane. As usedherein, an “electrochromic device precursor” is an EC device, typicallya stack of thin films as described above, applied or deposited on asubstrate prior to the cutting of that substrate into individual ECdevices. As such, multiple EC device precursors are fabricated on anysingle substrate, or as described herein, substrate daughter pane.Typically, the EC precursor layout is designed to incorporate sufficientspace between the precursors to allow for cutting, preferably withoutdamaging any films or the stack in general.

In some embodiments, the EC device (or precursor) 32 is produced, ingeneral, by coating or applying the EC stack 21 on a large substratepanel 31, such as annealed glass. The stack may be applied or depositedaccording to those methods known in the art and as incorporated herein.The EC device (or precursor) 32 is then subsequently cut (by traditionalmechanical means, by laser cutting, or by electrothermal cuttingmethods, detailed herein) to a desired dimension depending on theultimate application. Of course, the panel may be cut into any size orshape. The substrate may also have been pre-cut from a larger panel. Thedevice 32 is then laminated to an EC outer laminate glass pane 22,preferably to provide additional mechanical strength. The EC laminate 29can be constructed with the EC device substrate 32 as shown in FIG. 1B(i.e. with the EC film stack 21 on the outside of the EC laminate 29) oralternatively, the EC laminate 29 can be constructed with the EC devicesubstrate 32 oriented with the EC film stack 21 in contact with theinterlayer material 28 (i.e. the EC film stack on the inside of thelaminate).

Once the EC device laminate 29 is processed, it is optionally combinedwith glass 20 to form an IGU 30.

In some embodiments, the EC outer laminate glass pane is about the samesize as the EC device. In other embodiments, the EC outer laminate glasspane is a different size than the EC device. In some embodiments, the ECsubstrate is indented relative to the outer glass pane, as describedabove. As further detailed herein, the EC outer laminate glass may haveabout the same or different thicknesses and/or coefficients of thermalexpansion as the EC device (or the substrate on which the EC device isdeposited). The outer laminate glass pane may be mechanically cut orlaser cut. Another aspect of the invention is a laminate made accordingto this process.

“Cut-then-Coat-then-Cut”

In another embodiment of the proposed invention, Applicants havediscovered a manufacturing approach which involves first cutting a largepanel of an EC substrate into one or more substrate daughter panels,followed by applying the ‘coat-then-cut’ concept described above, suchas to each of the one or more substrate daughter panels (this process ishereinafter referred to as a “cut-then-coat-then-cut” process).

As such, another aspect of the present invention is a process ofmanufacturing an electrochromic device laminate comprising providing anelectrochromic substrate; cutting the electrochromic substrate into oneor more substrate daughter panels; fabricating a plurality ofelectrochromic device precursors on each of the one or more substratedaughter panels; cutting each of the electrochromic device precursorsinto individual electrochromic devices; and laminating each of theindividual electrochromic devices to a separate outer laminate glasspane.

In some embodiments, a large substrate panel of annealed glass is cutinto one or more substrate daughter panels. In other embodiments, alarge substrate panel of annealed glass is cut into a plurality ofsubstrate daughter panels. Each of the substrate daughter panels may beabout the same size and/or shape, or may be different sizes and/orshapes. For example, the initial large EC substrate may be cut intothree equally sized substrate daughter panels or may be cut into threesubstrate daughter panels with each having a different size. At leastsome of the edges of the substrate daughter panels may then undergo anoptional edge grinding process, followed preferably, by washing. Inother embodiments, the large substrate panel is cut into a singlesmaller (in at least one dimension) substrate daughter panel.

In some embodiments, the substrate daughter panels are loaded ontocarriers for further processing, i.e. fabrication of the EC deviceprecursors by coating each of the substrate daughter panels with an ECstack as described herein. Any number of substrate daughter panels maybe loaded onto any single carrier, but it is preferred to optimize thesurface area of the carrier with as many substrate daughter panels aswill fit. Each of the EC device precursors on each of the substratedaughter panels are then further cut, such as by a laser orelectrothermal cutting, or by mechanical means.

It is believed that the cut-then-coat-then-cut process provides severaladvantages. First, it is typical that the glass substrate is held at aslight angle during a sputtering process (usually between about 5degrees and 9 degrees relative to vertical). This angle could lead to adeflection which could ultimately lead to non-uniform coatings due tothe bowing of glass. It is believed that this bowing of glass increasesas the size of the glass increases. As such, applying coatings (e.g., ECstacks) via sputtering on smaller pieces of glass, first cut from alarger substrate panel, could assist in alleviating any potentialnon-uniformity. In some embodiments, the substrate glass is heldvertically during coating. Without wishing to be bound by any particulartheory, it is also believed that bowing could be caused by thermalstresses. It is believed that any thermal stresses could likewise bereduced by using substrate daughter panels, preferably smaller substratedaughter panels.

Second, certain desired substrate glass sizes (or shapes) are not alwaysavailable from a manufacturer. For example, glass from a manufacturermay be too large to fit in a carrier or in a reactive sputteringchamber. Moreover, it may be more cost effective to buy larger pieces ofglass and first cut them to fit into a carrier.

Third, it is believed that the edges of the as-received glass may notalways be in a condition suitable for immediate processing. In thesecases, it is desirable to first cut the glass into smaller daughterpanels having a defect free edge or an edge that meets downstreammanufacturing and processing requirements.

Fourth, any piece of large glass may contain a defect. A glass panel(s)without the defect can be cut from the large glass panel, withoutwasting large amounts of glass or processing time.

The lamination step in the “coat-then-cut” and the“cut-then-coat-then-cut” processes are carried out using methods knownto those of skill in the art. For example, typical lamination processesinclude heating the laminate under moderate pressures to create apartial bond between the glass panels, e.g. a nip roller process,followed by an extended bonding process, e.g. using an autoclave, atelevated temperatures and pressures to complete the bonding to the glassand either remove residual air or dissolve the air into the polymerstructure to create an optically-clear interlayer. Other approachesutilize either: (i) a vacuum process combined with heating to remove airfrom the interlayer region and bond the glass panels, or (ii) a polymerthat is poured into the gap between the glass panels that fills thecapillary space between to create a transparent interlayer.

Conventional Mechanical Scribe or Cutting

Typical glass preparation involves creating a cut on the surface of theglass panel using a carbide or a diamond tip scribe or wheel, thenapplying a bending moment to propagate surface cracks along the edge tocreate, it is believed, a straight cut. The edges of glass are oftenground using a grinder or silicon carbide sanding belt.

Laser Cutting

In some embodiments of the present invention, a laser is used to cut theEC device laminate 29 or the EC substrate 31. As used herein, the term“laser cut” means (i) using a laser to create a thin crack perpendicularto the substrate surface which is subsequently propagated through theglass by an applied bending moment to produce a complete separation, or(ii) a complete cut through the glass by a laser-induced crack that ispropagated along the length of the substrate to complete separation. Theprocess of laser cutting is equally applicable to the “coat-then-cut”and the “cut-then-coat-then-cut” processes.

Thus, in one aspect of the present invention is a process ofmanufacturing an electrochromic device laminate comprising providing anelectrochromic substrate; fabricating a plurality of electrochromicdevice precursors on the substrate; laser cutting each of theelectrochromic device precursors into individual electrochromic devices;and laminating each of the individual electrochromic devices to aseparate outer laminate glass pane. In some embodiments, the lasercutting process involves either inducing a thin surface crack laterpropagated to separation by application of a bending moment, or acomplete “cut-through” by initiating and propagating a crack along thesubstrate to complete separation with no subsequent bending or“breakout” required.

More specifically, a thermally tough, innovative laminated outer glazingis fabricated using a focused laser beam to facilitate cutting of thecoated glass substrates into individual daughter panes. Without wishingto be bound by any particular theory, it is believed that the laserenergy locally heats the glass followed by rapid cooling along theseparation lines. This results in crack formation perpendicular to theglass resulting in an edge that is free of chips and additionalmicrocracks that may cause contamination and edge weakening,respectively. The resultant laser processed edge does not require anyadditional edge finishing.

In some embodiments, it is believed that the laser-cut edges canwithstand stresses about 2 to about 3 times higher than standardmechanically cut edges and, it is believed, are of comparable edgestrength to heat-strengthened glass. Consequently, it is believed thatthe laser cut, untempered EC device substrates can withstand temperaturevariations, and hence the stresses associated with such temperaturevariations, that are typically generated in the field when the glass isdeeply tinted.

In some embodiments, the laser cut panels are able to withstand stressesof at least about 60 MPa. In other embodiments, the laser cut panels areable to withstand stresses of at least about 69 MPa. In yet otherembodiment, the laser cut panels are able to withstand stresses of atleast about 75 MPa. In yet other embodiment, the laser cut panels areable to withstand stresses of at least about 100 MPa. In even furtherembodiments, the laser cut panels are able to withstand stress ofbetween about 70 MPa and about 310 MPa.

Electrothermal Cutting

In some embodiments of the present invention, electrothermal cutting(ETC) is used to cut or separate the ED device laminate 20 or the ECsubstrate 31. ETC refers to a method of heating (and where required,evaporating) small regions within an insulating or semiconductingsubstrate. In some embodiments, the glass is cut by the application ofan AC electrical discharge between two electrodes. Without wishing to bebound by any particular theory, it is believed that the high voltagelocally heats the glass and a cooling head causes suitable stress tocreate a through crack to form. The electrode/cooling head assembly isthen moved in a defined path to propagate the crack (controlledseparation) in the desired pattern defined by the custom size of therequired EC substrate or EC substrate daughter panel.

In some embodiments, the panels cut by ETC are able to withstandstresses similar to those cut by laser. In other embodiments, the panelscut by ETC are able to withstand stresses of at least about 60 MPa. Inyet other embodiments, the panels cut by ETC are able to withstandstresses of at least about 69 MPa. In further embodiments, the panelscut by ETC are able to withstand stresses of at least about 75 MPa. Inyet further embodiments, the panels cut by ETC are able to withstandstresses of at least about 80 MPa. In even further embodiments, thepanels cut by ETC are able to withstand stresses of at least about 100MPa.

EXPERIMENTAL DATA AND EXAMPLES Laminate Impact Testing Results

Impact testing was performed on “mismatched” laminates comprising: (1)an EC substrate 31, comprised of annealed soda-lime float glass orlow-CTE glass; and (2) an EC outer laminate glass pane 22, comprisedeither of a heat strengthened glass, tempered glass, or annealed glass,as shown in FIG. 4. The impact data suggest a useful design window withrespect to EC substrate 31 and EC outer laminate glass pane 22thicknesses. Polyvinylbutyral (PVB) and ionomer polymers (SGP fromDuPont) were tested as interlayer materials 28. The SGP showed anarrower design window with respect to EC substrate/support substrateand interlayer thickness compared to PVB which, without wishing to bebound by any particular theory, it is believed better PVB performance isrelated to the enhanced compliance/stretching of the PVB material.

FIG. 4 summarizes impact testing data as function of EC substrate 31, ECouter laminate glass pane 22, and interlayer 28 thickness. FIG. 4demonstrates different combinations of EC substrate 31 thickness, ECouter laminate glass pane 22 thickness and interlayer material 28thickness. For the 34″×76″ test geometry required by ANSI Z97.1-2004,the data suggested application over a wide range of glass and interlayerthicknesses. It is believed that PVB, is more robust with respect toglass and interlayer thicknesses.

The most widely referenced test standard for lamination glazing isissued by American National Standards Institute standard, ANSIZ97.1-2004 (American National Standard for Safety Glazing Materials Usedin Buildings—Safety Performance Specifications Method of Test). Thisstandard establishes both the specifications and methods of testing forsafety glazing materials as used for building and architecturalpurposes. The testing involves impact of a 100 pound bag of lead shotheld at the end of a tether and swung into the centerline of a laminatedglass panel. There is an additional standard issued by the ConsumerProducts Safety Council (CPSC), 16CFR1201, that uses the same testmethodology but has slightly different pass/fail criteria.

The pass/fail criteria for the Z97.1 and 16CFR1201 tests are slightlydifferent. The Z97.1 test allows breakage and formation of a tear/holesmaller than would allow a 3-inch diameter ball to pass through. The16CFR1201 test additionally requires that a 3-inch ball weighing 4pounds will not fall through the opening after 1 second duration whenthe panel is in a horizontal position. The pass/fail data reported arebased on Z97.1 criteria, but the rigidity of the laminate would, webelieve, allow for a 16CFR1201 pass.

Both tests have different categories, depending on the height of the bagdrop. We present results from the most extreme test involving a dropfrom a height of 48″ (400 foot-pounds). Typical test panel sizes are34″×76″ although another size (40″×40″) was also tested. The 40″×40″geometry represents a more challenging test. All glass substrates forimpact testing in Examples 1-8, which follow, were cut by mechanicalscribing. Testing was performed at SAGE of Faribault, Minn. and atCardinalLG in Amery, Wis.

Examples Example 1 EC Laminate

Component Material Properties EC outer laminate Fully temperedThickness: 3.2 mm glass pane soda-lime glass CTE: 8.5 ppm/K EC substrateAnnealed soda-lime Thickness: 1.7 mm float glass CTE: 8.5 ppm/KInterlayer material PVB Thickness: 0.76 mm

Method of Manufacture:

The laminated EC structure of Example 1 was manufactured according to a“cut-then-coat” process. The lamination was performed using aconventional nip roller/autoclave process. Equivalent results could beobtained using a vacuum laminating process.

Results:

The laminated EC structure having the components detailed above passedthe ANSI Z97.1 standard for impact testing.

Example 2 EC Laminate

Component Material Properties EC outer laminate Fully temperedThickness: 4 mm glass pane soda lime glass CTE: 8.5 ppm/K EC substrateAnnealed soda-lime Thickness: 1.7 mm float glass CTE: 8.5 ppm/KInterlayer material PVB Thickness: 0.76 mm

Method of Manufacture:

The laminated EC structure of Example 2 was manufactured according to a“cut-then-coat” process. The lamination was performed using aconventional nip roller/autoclave process.

Results:

The laminated EC structure having the components detailed above passedthe ANSI Z97.1 standard for impact testing.

Outer laminate panels having different thicknesses were tested inExamples 1 and 2, with the resulting laminates both passing impacttesting. Equivalent results could be obtained using a vacuum laminatingprocess.

Example 3 EC Laminate

Component Material Properties EC outer laminate Fully temperedThickness: 3.2 mm glass pane soda-lime glass CTF: 8.5 ppm/K EC substrateAnnealed soda-lime Thickness: 1.7 mm float glass CTE: 8.5 ppm/KInterlayer material SentryGlas Plus Thickness: 0.89 mm (DuPont)

Method of Manufacture:

The laminated EC structure of Example 3 was manufactured according to a“cut-then-coat” process. The lamination was performed using aconventional nip roller/autoclave process.

Results:

The laminated EC structure having the components detailed above passedthe ANSI Z97.1 standard for impact testing. Equivalent results could beobtained using a vacuum laminating process.

Example 4 EC Laminate

Component Material Properties EC outer laminate Fully temperedThickness: 4 mm glass pane soda-lime glass CTF: 8.5 ppm/K EC substrateAnnealed soda-lime Thickness: 1.7 mm float glass CTE: 8.5 ppm/KInterlayer material SentryGlas Plus Thickness: 0.89 mm (DuPont)

Method of Manufacture:

The laminated EC structure of Example 4 was manufactured according to a“cut-then-coat” process. The lamination was performed using aconventional nip roller/autoclave process.

Results:

The laminated EC structure having the components detailed above passedthe ANSI Z97.1 standard for impact testing.

Outer laminate panels having different thicknesses were tested inExamples 3 and 4, with the resulting laminates both passing impacttesting. Equivalent results could be obtained using a vacuum laminatingprocess.

Example 5 EC Laminate

Component Material Properties EC outer laminate Fully temperedThickness: 4 mm glass pane soda-lime glass CTE: 8.5 ppm/K EC substrateAnnealed borofloat Thickness: 1.7 mm CTE float glass CTE: 3.3 ppm/KInterlayer material PVB Thickness: 0.76 mm

Method of Manufacture:

The laminated EC structure of Example 5 was manufactured according to a“cut-then-coat” process. The lamination was performed using aconventional nip roller/autoclave process.

Results:

The laminated EC structure having the components detailed above passedthe ANSI Z97.1 standard for impact testing. Equivalent results could beobtained using a vacuum laminating process.

Example 6 EC Laminate

Component Material Properties EC outer laminate Heat-strengthenedThickness: 2.3 mm glass pane soda-lime float CTE: 8.5 ppm/K glass ECsubstrate Annealed soda-lime Thickness: 1.7 mm float glass CTE: 8.5ppm/K Interlayer material SentryGlas Plus Thickness: 1.5 mm (DuPont)

Method of Manufacture:

The laminated EC structure of Example 6 was manufactured according to a“cut-then-coat” process. The lamination was performed using aconventional nip roller/autoclave process.

Results:

The laminated EC structure having the components detailed above passedthe ANSI Z97.1 standard for impact testing. Equivalent results could beobtained using a vacuum laminating process.

Example 7 EC Laminate

Component Material Properties EC outer laminate Heat strengthenedThickness: 2.3 mm glass pane soda-lime float CTE: 8.5 ppm/K glass ECsubstrate Annealed soda-lime Thickness: 1.7 mm float glass CTE: 8.5ppm/K Interlayer material PVB Thickness: 0.76 mm

Method of Manufacture:

The laminated EC structure of Example 7 was manufactured according to a“cut-then-coat” process. The lamination was performed using aconventional nip roller/autoclave process.

Results:

The laminated EC structure having the components detailed above passedthe ANSI Z97.1 standard for impact testing. Equivalent results could beobtained using a vacuum laminating process.

Example 8 SageGlass® EC Device

Component Material Properties Interior Glass of fully temperedThickness: 6 mm IGU soda-lime float CTE: 8.5 ppm/K glass EC substratefully tempered Thickness: 6 mm soda-lime float CTE: 8.5 ppm/K glass

Method of Manufacture:

The IGU of Example 8 was manufactured according to the standardmanufacturing processes described herein.

Results:

The IGU having the components detailed above passed the ANSI Z97.1standard for impact testing.

It has been observed that the laminated IGUs of Examples 1-7 and thetraditional IGU of Example 8 all passed ANSI Z97.1 for impact testing.Thus, it is believed that the EC device laminates (and IGUs comprisingthem) of the present invention are capable of meeting/exceeding allcritical industry mechanical performance requirements for architecturalapplications.

Comparison of Mechanically-Scribed Annealed, Laser-Cut Annealed andHeat-Strengthened Soda-Lime Float Glass Edge Strength

We have evaluated laser cut edge strength for a variety of glasscompositions, substrate thicknesses and mechanical testing sampleorientations. The best quantitative measurement of edge strength forlaser cut glass has been performed using a four-point bend test setup.In the four-point bend, an example using a ‘lying down’ sampleorientation shown in FIG. 5, the entire region under the inner span issubjected to the same bending moment, and therefore, it is believed,allows for a larger effective area to be interrogated. We have testededge strength in both ‘edge-on’ and ‘lying down’ orientations. The‘edge-on’ orientation was initially used because it allows for testingof both top and bottom edges at the same time, in similar stressconditions as would be seen in service. However, we have found excellentagreement with data in both test orientations, and since the ‘lyingdown’ is easier to test using a conventional four-point bend testfixture, we have tested the majority of test samples in the ‘lying down’orientation. Typical sample dimensions were 25 mm wide and 330 mm longwith an effective test region of about 100 mm. We have examined avariety of different glass thicknesses (ranging from approximately 1 mmto 2.3 mm) and glass compositions including standard soda-lime floatglass from various manufacturing sources, and low CTE glasses includingEagle2000™ and EagleXG™ (manufactured by Corning) and Borofloat33™(manufactured by Schott Glass).

We have compared our laser cut edge strength data on soda-lime glass toedge strength literature values for annealed, heat-strengthened andfully tempered soda-lime glasses. Veer et al. has recently published acomprehensive experimental study comparing annealed, heat-strengthenedand tempered glass. Veer, FA, PC Louter and FP Bos, “The strength ofannealed, heat-strengthened and fully tempered float glass,” Fatigue &Fracture of Engineering Materials & Structures, 32 pp. 18-25 (2009).Because of the minimum size constraints involved with heat-strengtheningor tempering, their sample dimensions (10×100×1000 mm with effectivetest length of about 500 mm) were significantly larger than in our studyand a direct comparison requires appropriate scaling since,statistically speaking, a larger area would have a higher probability ofincluding a critically-sized flaw at a given stress. We used a treatmentbased on the work of Vuolio (2003) and Beason and Lignell (2002) Beason,W L and A W Lignell, “A Thermal Stress Evaluation Procedure forMonolithic Annealed Glass”, Symp. on the Use of Glass in Buildings, ASTMSTP1434, ed. VL Block (2002), in which the strengths for differentsample sizes are proportional to the ratio of the respective edge areas:

σ₁/σ₂=(Area₂/Area₁)^(1/m)

The Weibull modulus, m, is a measure of the variation in the respectivestrength distribution. A value of m=5.8, determined from theexperimental data, was used for the calculations. This corresponded to aratio of 1.7.

The area-adjusted data comparing in-house and literature test resultsare shown in FIG. 6. Comparison of in-house and literature data suggestthat the laser-cut test data lie in-between the distributions forheat-strengthened (“HS”) and fully tempered (“FT”) literature data.

FIG. 6 further shows a comparative probability plot of edge strength formechanical and laser scribing. It is believed that the laser scribedpanels show a strength of at least 60 MPa. In some embodiments, thestrength of the laser scribed panels is at least 69 MPa, preferablyabout 75 MPa, more preferably about 100 MPa.

FIG. 6 also provides a comparison of experimental testing (mechanical(“Mechanical Scribe”) and (“Laser cut”) and literature data (adjustedfor differences in test sample geometry). Our test data for annealedsamples made using conventional mechanical scribe and laser cutprocesses are shown as triangles and squares, respectively in FIG. 6. Ingeneral, the strength distribution of laser-cut glass (representing thetotal data from five different laser cutting campaigns using differentlaser cutting machines) can be described as having a performance betweenHS and FT performance.

Example 9 Laser-Cut Laminate

Component Material Properties EC outer laminate Fully-temperedThickness: 3.2 mm glass pane soda-lime float CTE: 8.5 ppm/K glass ECsubstrate Annealed soda-lime Thickness: 1.7 mm float glass CTE: 8.5ppm/K Interlayer material PVB Thickness: 0.76 mm

Method of Manufacture:

The laser-cut laminate of Example 9 was manufactured according to a“coat-then-cut” process. The lamination was performed using aconventional nip roller/autoclave process. The EC substrate (EC deviceor device precursor) was laser-cut, as described herein, after the ECstack was deposited. The laser-cut laminate edge strength was measuredby inducing edge stresses by creation of a temperature gradient in thesample. The temperature gradient was created using a silicone heatingpad that was smaller in laterial dimensions compared to the laminate.The pad was placed on the surface of the laminate with an unheatedperimeter about 25 mm wide. The magnitude of the gradient was controlledby adjusting the applied power to the heating pad (controlled by avariac variable power supply) while keeping the laminate edges near roomtemperature. The edge stresses created by the induced temperaturegradient were directly measured using photoelastic techniques (StressPhotonics, Inc., Madison, Wis.).

Results:

The laser-cut, laminated EC structures having the components detailedabove had an edge strength of at least about 60 MPa after lamination.

A process capability study of as-fabricated thermal laser scribe (TLS)processing was also performed. The study used the mechanical, four-pointbend test described above. Data from over 80 samples from five testingsessions were collected. The data, representing five different TLScampaigns over a six-month period, were used to develop a processcapability based on different maximum in-service edge stresses. Theprocess capability Cpk suggested that the as-fabricated strength wassufficient to provide a low probability of failure in the operationalstress environment for EC device laminate window applications.

In order to calculate process capability using conventional statisticalmethods, it was required that the data have a normal distribution. TheTLS mechanical test data followed a lognormal distribution and requireda logarithmic transformation to achieve normality. Process capabilityvalues and corresponding predicted failure rates were calculated for anumber of lower specification limits (i.e. maximum edge stresses) todetermine the sensitivity to device thermal gradients. The maximum edgestress depends on the environmental interaction as well as window orarchitectural frame design (e.g. fully insulated frames versus heat sinkdesigns). Capability analyses were calculated using Minitab15statistical software package.

Calculated breakage probability v maximum edge stress Maximum stressProbability of (MPa) breakage 117 0.171 103 0.0910000 90 0.0380000 830.0220000 69 0.0048000 55 0.0005300 41 0.0000160 34 0.0000010 280.0000001

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

1.-28. (canceled)
 29. A process, comprising: providing an electrochromicsubstrate; fabricating electrochromic device precursors on theelectrochromic substrate; cutting the electrochromic substrate intoindividual electrochromic devices, wherein cutting comprises inducing asurface crack in the electrochromic substrate and applying a bendingmoment to propagate the surface crack and separate the electrochromicdevices from each other; and laminating each of the individualelectrochromic devices to a corresponding glass pane.
 30. The process ofclaim 29, wherein inducing the crack forms the crack only partly throughand not completely through a thickness of the electrochromic substrate.31. The process of claim 29, wherein cutting the electrochromicsubstrate comprises locally heating the electrochromic substratefollowed by rapid cooling along a separation line.
 32. The process ofclaim 29, wherein each of the individual electrochromic devices has anedge strength of at least 60 MPa.
 33. The process of claim 29, whereineach of the individual electrochromic devices has an edge strength of atleast 75 MPa.
 34. The process of claim 29, wherein each of theindividual electrochromic devices has an edge strength of at least 100MPa.
 35. The process of claim 29, wherein: a layout for theelectrochromic device precursors has a space between the electrochromicdevice precursors; and cutting includes cutting the electrochromicsubstrate along the space between the electrochromic device precursors.36. The process of claim 29, wherein laminating is performed such thatan interlayer is disposed between the electrochromic substrate and itscorresponding glass pane.
 37. The process of claim 29, wherein theinterlayer comprises a polyvinylbutyral, an ionomeric material, anethylenevinyl acetate, a polyurethane, or a mixture thereof.
 38. Theprocess of claim 29, wherein cutting comprises laser cutting.
 39. Theprocess of claim 29, wherein cutting comprises electrothermal cutting.40. The process of claim 29, wherein cutting comprises mechanicalcutting.
 41. The process of claim 29, wherein each of the individualelectrochromic devices is smaller than its corresponding glass pane inat least one dimension.
 42. The process of claim 41, wherein each of theindividual electrochromic devices is indented about 0.5 mm to about 3 mmrelative to the its corresponding glass pane in at least one dimension.43. A process, comprising: providing an electrochromic substrate;cutting the electrochromic substrate into one or more substrate daughterpanes, wherein cutting includes inducing a surface crack in theelectrochromic substrate and applying a bending moment to propagate thesurface crack and separate the electrochromic substrate into thedaughter panes; fabricating electrochromic device precursors on each ofthe one or more daughter panes; cutting the one or more daughter panesto form individual electrochromic devices, wherein each of theindividual electrochromic devices includes a portion of the one or moredaughter panes and at least one of the electrochromic device precursors;and laminating each of the individual electrochromic devices to acorresponding glass pane.
 44. The process of claim 43, wherein inducingthe surface crack forms the surface crack only partly through and notcompletely through a thickness of the electrochromic substrate.
 45. Theprocess of claim 43, wherein cutting the electrochromic substratecomprises locally heating the electrochromic substrate followed by rapidcooling along a separation line.
 46. The process of claim 43, whereineach of the individual electrochromic devices has an edge strength of atleast 60 MPa.
 47. The process of claim 29, wherein cutting compriseslaser cutting or electrothermal cutting.
 48. A process, comprising:providing an electrochromic substrate; fabricating electrochromic deviceprecursors on the electrochromic substrate, wherein a layout for theelectrochromic device precursors has a space between electrochromicdevice precursors; laser cutting the electrochromic substrate along thespace between the electrochromic device precursors into individualelectrochromic devices, wherein: laser cutting comprises inducing asurface crack only partly through, and not completely through, athickness of the electrochromic substrate, and applying a bending momentto propagate the surface crack and separate the electrochromic devicesfrom each other; laser cutting the electrochromic substrate includeslocally heating the electrochromic substrate followed by rapid coolingalong a separation line; and each of the individual electrochromicdevices has an edge strength of at least 75 MPa; and laminating each ofthe individual electrochromic devices to a corresponding glass pane,wherein each of the individual electrochromic devices is smaller thanits corresponding glass pane in at least one dimension.